When observing a comet please try to forget how bright you think the comet
should be, what it was when you last viewed it, what other observers think
it is or what the ephemeris says it should be.

The equations for the light curves of comets that are currently visible
use only the raw observations and should give a reasonable prediction for
the current brightness. If the comet has not yet been observed or has
gone from view a correction for aperture is included, so that telescopic
observers should expect the comet to be fainter than given by the equation.
The correction is about 0.033 per centimetre. Values for the r parameter
given in square brackets [ ] are assumed. The form of the light curve is
either the standard m = H0 + 5 log d + K0 log r or the linear brightening
m = H0 + 5 log d + L0 abs(t - T + D0) where T is the date of perihelion,
t the present and D0 an offset, if L0 is +ve the comet brightens towards
perihelion and if D0 is +ve the comet is brightest prior to perihelion.

Full details of recently discovered objects will not appear until they are
available on the CBAT web pages. The actual accuracy of preliminary orbits is often
(nearly always) much worse than the published
accuracy implies. In part this is because
each orbital solution is treated as a mathematical construct and does not take account of observational
error. JPL does publish the errors, whereas the MPECs do not.

2017 A1 (PanSTARRS)
A 19th magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on January 2.33.
[CBET 4340, MPEC 2017-A31, 2017 January 6] The comet was at perihelion at 2.3 au in 2017 May.
2017 A2 (348P/PanSTARRS)
A 21st magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on January 2.58.
It was then subsequently linked to images found in PanSTARRS and Mt Lemmon data from 2011 January, at which return it
was given the designation 2011 A5.
[CBET 4341, MPEC 2017-A32, 2017 Janaury 6] The comet was at perihelion at 2.2 au in 2016 June and has a period
of 5.6 years.
2017 A3 (Elenin)
Leonid Elenin discovered an 18th magnitude comet with the ISON-SSO 0.4m reflector at
Siding Spring on January 5.46. [CBET 4344, MPEC 2017-A75, 2017 January 11] The comet was
at perihelion at 3.9 au in 2017 January and has a period of around 300 years.
2017 AB5 (PanSTARRS)
An apparently stellar 21st magnitude object was discovered in PanSTARRS 1 images taken with the 1.8m
Ritchey-Chretien on January 3.41 and given an asteroidal designation. The same object was re-discovered by PanSTARRS
on 2018 January 5.50, but this time showing cometary features. Additional PanSTARRS images from 2017 December 9 were
also found. It was posted on the PCCP as P10FRqY.
[CBET 4468, MPEC 2018-A26, 2018 January 8] The comet is at perihelion at 9.2 au in 2018 February.
A/2017 AX13 [PanSTARRS]
PanSTARRS discovered a 22nd magnitude asteroid in images taken with the 1.8m Ritchey-Chretien on
January 2.58. [MPEC 2017-A67, 2017 January 9] The asteroid, classified as a Trans-Neptunian Object,
was at perihelion at 3.2 au in 2016 January and has a period of around 200 years and is in a retrograde
orbit with an inclination of 137°.
2017 B1 (349P/Lemmon)
A 21st magnitude object was discovered in PanSTARRS 1 images taken with the 1.8m
Ritchey-Chretien on January 26.59. This was quickly linked to asteroid 2010
EY90 discovered by the Mt Lemmon Survey with the
1.5m reflector on 2010 March 14.24 and with pre-discovery Mt Lemmon images from 2017
January 7. [CBET 4348, 4349, MPEC 2017-B82, 2017 January 27] The comet
was at perihelion at
2.5 au in 2017 August and has a period of 6.75 years.
2017 B2 (350P/McNaught)
Jim Scotti recovered 2010 J5 (P/McNaught) with the Spacewatch 1.8m reflector on January 26.52. It
returns to perihelion in 2018 January. [CBET 4352, MPEC 2017-B123, 2017 January 29/30]
2017 B3 (LINEAR)
A 19th magnitude object discovered by LINEAR (The 3.5m reflector Space Surveillance
Telescope at the Atom Peak site) on January 26.43 was shown to have cometary features by astrometrists after posting on
the PCCP. [CBET 4354, MPEC 2017-C43, 2017 February 4] The
comet has perihelion at 3.9 au in 2019 February.
2017 B4 (P/PanSTARRS)
A 21st magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on January 28.39.
[CBET 4355, MPEC 2017-C46, 2017 February 4] The comet was near perihelion at 2.8 au and has a period
of 9.3 years.
2017 B5 (354P/LINEAR)
2010 A2 (P/LINEAR) was recovered as an apparently asteroidal object via CCD images taken by Y. Kim with the 8.1-m
"Gemini North" telescope at Mauna Kea on January 26.43. The indicated correction to the prediction by S. Nakano in the ICQ's 2017
Comet Handbook is Delta(T) = +0.16 day. [CBET 4405, MPEC 2017-M38, 2017 June 21]
2017 C1 (NEOWISE)
A 20th magnitude comet was discovered from the NEOWISE satellite on February 6.09. [CBET
4358, MPEC 2017-C82, 2017 February 12] The comet was at perihelion at 1.5 au in 2017
January and has a period of around 90 years.
2017 C2 (PanSTARRS)
A 20th magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on February 4.26.
[CBET 4362, MPEC 2017-D22, 2017 February 19] The comet was at perihelion at 2.4 au in 2017 January and has a period
of about 1400 years.
A/2017 CW32 [Mt Lemmon]
The Mt Lemmon Survey discovered an asteroid in images taken with the 1.5m
reflector on February 2, which was posted on the PCCP. There is no evidence for cometary activity.
The asteroid is classified as an Unusual Object by the MPC and as a TNO by JPL.
It was at perihelion at 3.0 au in 2017 May and has a retrograde orbit with a period of around 2700 years.
It was placed on the PCCP as YCAD73A. In March it appeared on the PCCP for a second time, with the id of P10zOqm.
A/2017 CX33 [PanSTARRS]
PanSTARRS discovered a 22nd magnitude asteroid in images taken with the 1.8m Ritchey-Chretien on
February 1.42. [MPEC 2017-D39, 2017 February 24] The asteroid, classified as a Trans-Neptunian Object,
was at perihelion at 10.4 au in 2017 April and has a period of around 600 years. It was placed on the PCCP
as P10zfMW.
2017 D1 (P/Fuls)
D Carson Fuls discovered a 20th magnitude comet in Mt Lemmon Survey images taken with the
1.5m reflector on February 21.35. Following this, pre-discovery images were found in PanSTARRS data from
2015 and 2016, and Mt Lemmon data from 2016 November.
[CBET 4365, MPEC 2017-E04, 2017 March 1] The comet was at perihelion at 2.7 au in 2016 June and has a
period of 10.5 years.
2017 D2 (Barros)
Brazilian amateur astronomer João Ribeiro de Barros discovered a 17th magnitude comet in images taken with
the 0.45m f/2.9 reflector of the SONEAR observatory on February 23.31. [CBET 4366, MPEC 2017-E05, 2017 March 1]
The comet was at perihelion at 2.5 au in 2017 July.
2017 D3 (ATLAS)
An 18th magnitude comet was discovered in images taken with the 0.5m Schmidt at Haleakala on February 23.61.
[CBET 4367, MPEC 2017-E06, 2017 March 1]. The comet was at perihelion at 5.0 au in 2017 April.
Carlos de la Fuente Marcos, Raúl de la Fuente Marcos and Sverre J. Aarseth in a paper "Where the Solar system meets
the solar neighbourhood: patterns in the distribution of radiants of observed hyperbolic minor bodies" published in
Monthly Notices of the Royal Astronomical Society Letters 2018, 476 (1): L1-L5 (May 1, 2018) suggest that it is
a possible contender for an interstellar comet. They also suggest another 8 possible objects.
2017 D4 (P/PanSTARRS)
A 21st magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on February 25.44.
There were pre-discovery PanSTARRS images from January, and Mt Lemmon ones from February.
[CBET 4368, MPEC 2017-E07, 2017 March 1] The comet was at perihelion at 2.8 au in 2016 September and has a period
of around 20 years.
2017 D5 (PanSTARRS)
A 21st magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on February 23.24.
There were pre-discovery PanSTARRS images from February 10.32. It had been posted on the NEOCP as P10zKZZ.
[CBET 4378, MPEC 2017-G04, 2017 April 2] The comet was at perihelion at 2.2 au in 2017 January and has a period of
around 1000 years.
A/2017 DW108 [LINEAR]
A 20th magnitude asteroid was discovered in images taken with the Space Surveillance Telescope 3.5m reflector
at the Atom site on February 22.16. [MPEC 2017-E02, 2017 March 1] The asteroid is classified as an Apollo asteroid
and was at perihelion at 0.5 au in 2017 April. It has a period of 3.8 years, with an Earth MOID of 0.037 au. It
will pass 0.086 au from the Earth on March 7 and 0.014 au from Venus on March 25. David Seargent notes that the
orbit has similarities with that of D/Helfenzreider, seen in 1766.
2017 E1 (Borisov)
Gennady Borisov discovered a 17th magnitude comet on March 1.10 with the 0.4-m f/2.3 astrograph at the MARGO
observatory, near Nauchnij, Crimea. [CBET 4369, MPEC 2017-E42, 2017 March 4] The comet
was at perihelion at
0.9 au in April. Unfortunately the circumstances are not good and the comet is not predicted to get brighter
than 14th magnitude.
2017 E2 (Tsuchinshan)
A comet was discovered at the Purple Mountain Observatory, XuYi station with the 1.04-m f/1.8 Schmidt on March 1.82.
It had been posted
on the NEOCP as X49504. [CBET 4370, MPEC 2017-E57, 2017 March 7] The
discovery MPEC gave the comet name as XuYi, but this was subsequently changed to
Tsuchinshan after a vote by the Working Group on Small Body Nomenclature. The comet was at perihelion at
2.4 au in 2016 May and has a period of around 100 years.
2017 E3 (PanSTARRS)
A 19th magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on March 7.53.
[CBET 4372, MPEC 2017-E85, 2017 March 13] The comet was at perihelion at 5.9 au
in 2017 May.
2017 E4 (Lovejoy)
Terry Lovejoy discovered a 15th magnitude comet in images taken with his 0.36m
f1.9 Schmidt-Cassegrain on March 9.68. [CBET 4373, MPEC 2017-E86, 2017 March 13]
The comet was soon shown to be significantly brighter than indicated by the CCD
observations, with Juan Jose Gonzalez estimating it at 8.6 in his 0.2m SCT on March 20.21.
The comet was at perihelion at 0.5 au in 2017 April. It was
intrinsically faint and having reached 7th magnitude did not survive perihelion.
2017 E5 (Lemmon)
A 20th magnitude object was discovered in Mt Lemmon Survey images taken with the
1.5m reflector on March 4.41. It had been posted on the NEOCP as YE832BC.
[CBET 4379, MPEC 2017-G05, 2017 April 2] The comet was at perihelion at
1.8 au in 2016 June and has a period of 8000 years.
A/2017 EM4 [Mt Lemmon]
The Mt Lemmon Survey discovered a 20th magnitude asteroid in images taken with the 1.5m
reflector on March 8.42. [MPEC 2017-E95, 2017 March 13]
The asteroid is classified as a Centaur by JPL.
It was at perihelion at 2.6 au in 2017 January and has a high inclination orbit with a period of around 100 years.
It has a Jupiter MOID of 2.5 au and a Tisserand invariant of 0.51.
2017 F1 (Lemmon)
A 20th magnitude object was discovered in Mt Lemmon Survey images taken with the
1.5m reflector on March 20.19. It had been posted on the NEOCP as YF982D7.
[CBET 4380, MPEC 2017-G06, 2017 April 2] The comet will reach perihelion at
4.5 au in 2017 December.
2017 F2 (PanSTARRS)
A 21st magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on March 31.41.
[CBET 4381, MPEC 2017-G56, 2017 April 6] The comet is at perihelion at 6.9 au in 2017
November.
A/2017 FF63 [Mt Lemmon]
The Mt Lemmon Survey discovered a 21st magnitude asteroid in images taken with the 1.5m
reflector on March 19.34. [MPEC 2017-F82, 2017 March 23]
The asteroid is classified as a member of the Outer Main-belt by JPL.
It was at perihelion at 1.6 au in 2017 February and has a period of around 6 years. The
orbit has a Jupiter MOID of 0.22 au and a Tisserand invariant of 2.78.
A/2017 FM64 [PanSTARRS]
PanSTARRS discovered a 22nd magnitude asteroid in images taken with the 1.8m Ritchey-Chretien on
March 19.33. [MPEC 2017-F101, 2017 March 24] The asteroid, classified as an Outer Main-belt Asteroid,
was at perihelion at 1.5 au in 2017 February and has a period of around 6.2 years. The
orbit has a Jupiter MOID of 0.06 au and a Tisserand invariant of 2.87.
A/2017 FP64 [NEOWISE]
A 19th magnitude asteroid was discovered from the NEOWISE satellite on March 20.97. [MPEC 2017-F104, 2017 March 24]
The asteroid, classified as an Amor, was at perihelion at 1.3 au in 2017
April and has a period of around 5.7 years. The
orbit has a Jupiter MOID of 0.06 au and a Tisserand invariant of 2.84.
A/2017 FA157 [PanSTARRS]
PanSTARRS discovered a 22nd magnitude asteroid in images taken with the 1.8m Ritchey-Chretien on
March 29.40. [MPEC 2017-G32, 2017 April 4] The asteroid, classified as an Outer Main-belt Asteroid,
was at perihelion at 1.5 au in 2017 February and has a period of around 6.2 years. The
orbit has a Jupiter MOID of 0.03 au and a Tisserand invariant of 2.86.
A/2017 FU158 [NEOWISE]
A 21st magnitude asteroid was discovered from the NEOWISE satellite on March 26.96. [MPEC 2017-G88, 2017 April 14]
The asteroid, classified as an Amor, was at perihelion at 1.2 au in 2017
January and has a period of around 6.8 years. The
orbit has a Jupiter MOID of 0.49 au and a Tisserand invariant of 2.58.
2017 G1 (P/PanSTARRS)
A 22nd magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on April 1.46.
There were also pre-discovery images from March 25.
[CBET 4382, MPEC 2017-G33, 2017 April 6] The comet was at perihelion at 2.6 au in 2016
May and has a period of about 22 years. It is a Jupiter-family Comet and has a MOID of 0.29 au.
2017 G2 (P/PanSTARRS)
A 20th magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m
Ritchey-Chretien on April 3.41. There were also pre-discovery images from March
18. [CBET 4384, 4385, MPEC 2017-H41, 2017 April 21] The comet was at perihelion
at 2.8 au in 2017 June and has a period of about 23 years. It is a
Jupiter-family Comet and has a MOID of 0.45 au.
It was placed on the PCCP as P10AMVu.
2017 G3 (PanSTARRS)
A 20th magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on April 7.57.
[CBET 4386, MPEC 2017-H42, 2017 April 21] The comet was near perihelion at 2.6 au. It was placed on the PCCP as P10APWl.
A/2017 GC8 [PanSTARRS]
PanSTARRS discovered a 22nd magnitude asteroid in images taken with the 1.8m Ritchey-Chretien on
April 1.46. [MPEC 2017-H32, 2017 April 21] The asteroid, classified as a Centaur,
was at perihelion at 2.6 au in 2017 March and has a period of around 33 years. The
orbit has a Jupiter MOID of 0.49 au and a Tisserand invariant of 2.37. It was placed on the PCCP
as P10AH43.
A/2017 GD8 [PanSTARRS]
PanSTARRS discovered a 21st magnitude asteroid in images taken with the 1.8m Ritchey-Chretien on
April 1.54. [MPEC 2017-H33, 2017 April 21] The asteroid, classified by JPL as a Trans-Neptunian Object,
was at perihelion at 2.3 au in 2017 February and has a period of around 300 years.
It was placed on the PCCP as P10AHWa.
A/2017 GY8 [PanSTARRS]
PanSTARRS discovered a 22nd magnitude asteroid in images taken with the 1.8m Ritchey-Chretien on
April 3.47. The asteroid, classified by JPL as a Centaur,
was at perihelion at 8.4 au in 2016 June and has a period of around 140 years.
It was placed on the PCCP as P10AMVL.
A/2017 GZ8 [Mt Lemmon]
The Mt Lemmon Survey discovered a 19th magnitude asteroid in images taken with the 1.5m
reflector on April 3.41.
The asteroid is classified as a Centaur by JPL and an "other unusual asteroid" by the MPC.
It was at perihelion at 4.0 au in 2017 February and has a period of 21.5 years. The
orbit has a Jupiter MOID of 0.03 au and a Tisserand invariant of 2.79.
It was placed on the PCCP as YGAC510.
A/2017 HW3 [Mt Lemmon]
The Mt Lemmon Survey discovered a 21st magnitude asteroid in images taken with the 1.5m
reflector on April 22.31. [MPEC 2017-H69, 2017 April 26]
The asteroid is classified as a member of the Outer Main-belt by JPL.
It was at perihelion at 1.3 au in 2017 June and has a period of around 5.7 years. The
orbit has a Jupiter MOID of 0.21 au and a Tisserand invariant of 2.75.
A/2017 HW48 [PanSTARRS]
PanSTARRS discovered a 21st magnitude asteroid in images taken with the 1.8m Ritchey-Chretien on
April 25.54. [MPEC 2017-J11, 2017 May 2] The asteroid, classified as an Amor,
was at perihelion at 1.25 au in 2017 July and has a period of 5.2 years. The
orbit has a Jupiter MOID of 0.48 au and a Tisserand invariant of 2.97. It is not currently getting close to
Jupiter, though it will pass 0.07 au from Mars in 2043 February.
A/2017 JB6 [PanSTARRS]
PanSTARRS discovered a 21st magnitude asteroid in images taken with the 1.8m Ritchey-Chretien on
April 25. The asteroid, classified by JPL as a Trans-Neptunian Object,
was at perihelion at 3.8 au in 2016 October and has a period of around 200 years.
It was placed on the PCCP as P10Bfr4.
2017 K1 (PanSTARRS)
A 20th magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m
Ritchey-Chretien on May 21.40. [CBET 4392, MPEC 2017-K34, 2017 May 24] The comet
is at perihelion at 7.3 au in 2018 March.
2017 K2 (PanSTARRS)
A 21st magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on May 21.49.
[CBET 4393, MPEC 2017-K35, 2017 May 24] The comet is at perihelion at 1.8 au in 2022
December. The comet
was over 16 au from the Sun at discovery. JPL and the MPC give
different absolute magnitudes for the comet, and it is likely that the future brightness evolution is
not well determined. The comet will be a southern hemisphere object when at its
brightest, but could be a binocular object for UK observers prior to perihelion.
The latest more conservative magnitude parameters suggest that it might only
reach 10th magnitude.

Studies of the orbit suggest that most likely it is a dynamically old comet, though there is a 30%
chance that it might be an interstellar object. JPL currently designate it as a Hyperbolic Comet.

2017 K3 (P/Gasparovic)
Goran Gasparovic, from Zagreb, Croatia, discovered a 19th magnitude comet in images taken by himself and Y Chen
with an iTelescope 0.5m f6.8 reflector at Siding Spring on May 22.60. After posting on the PCCP, pre-discovery
images from the day before were found in Polonia Observatory images. [CBET 4396, MPEC 2017-L03, 2017 June 1]
The comet was near perihelion at 2.3 au and has a period of around 13 years. It is a Jupiter family comet.
2017 K4 (ATLAS)
A 17th magnitude comet was discovered in images taken with the 0.5m Schmidt at Haleakala on May 26.51
by the ATLAS (Asteroid Terrestrial-impact Last Alert System) team.
[CBET 4397, MPEC 2017-L04, 2017 June 1]. The comet is at perihelion at 2.5 au in 2018 January.
2017 K5 (PanSTARRS)
A 22nd magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on May 27.46.
[CBET 4398, MPEC 2017-L05, 2017 June 1] The comet is at perihelion at 7.6 au in 2020 March. The error bars
on the perihelion distance are 2.1 au and 58 days on the date of perihelion according to JPL.
2017K6 (Jacques)
Cristovao Jacques discovered an 18th magnitude comet on images taken with the SONEAR Observatory 0.45m reflector
on May 29.31 [CBET 4399, MPEC 2017-L06, 2017 June 1]. The comet has perihelion at 2.0 au in 2018 January.
2017 L1 (352P/Skiff)
H Sato recovered 2000 S1 (P/Skiff) on June 5.81 using the 0.51m i-Telescope at Siding Spring.
The indicated correction to the prediction by S. Nakano in the ICQ's 2017
Comet Handbook is Delta(T) = -2.64 days. [CBET 4402, MPEC 2017-L51, 2017 June 6]
2017 M1 (353P/McNaught)
K. Sarneczky and R. Konyves-Toth recovered 2009 S2 (P/McNaught) using the 0.60-m Schmidt telescope at the
Piszkesteto Station of Konkoly Observatory. The indicated correction to the prediction by S. Nakano in the ICQ's 2017
Comet Handbook (p. H13) is Delta(T) = -0.06 day. [CBET 4404, MPEC 2017-M28, 2017 June 20]
2017 M2 (355P/LINEAR-NEAT)
2004 T1 (P/LINEAR-NEAT) was recovered with the 1.0m reflector at the European Space Agency's Optical Ground Station at Tenerife
on June 21.17. The indicated correction to the prediction by B. G. Marsden on MPC 89018 is
Delta(T) = -0.57 day. The 2011 return was missed because the comet
was in conjunction with the sun while near perihelion. [CBET 4406, MPEC 2017-M40, 2017 June 22]
2017 M3 (PanSTARRS)
A 21st magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on June 20.29.
It was placed on the PCCP as P10BB32.
[CBET 4407, MPEC 2017-M44, 2017 June 23] The comet was near perihelion at 4.7 au.
2017 M4 (ATLAS)
An 18th magnitude comet was discovered in images taken with the 0.5m Schmidt at Haleakala on June 21.58
by the ATLAS (Asteroid Terrestrial-impact Last Alert System) team. There were PanSTARRS images from June 16.57.
[CBET 4408, MPEC 2017-M45, 2017 June 23]. The comet is at perihelion at 3.3 au in 2019 January.
2017 M5 (TOTAS)
A 19th magnitude comet was discovered in images taken during the Teide Observatory Tenerife Asteroid Survey with the 1.0m
reflector of the ESA Optical Ground Station on June 23.07. [CBET 4410, MPEC 2017-N25, 2017 July 1]. The comet is at perihelion at 6.0 au in 2018
June.
A/2017 MB1 [Mt Lemmon]
The Mt Lemmon Survey discovered a 19th magnitude asteroid in images taken with the 1.5m
reflector on June 19.41. [MPEC 2017-M48, 2017 June 23] The asteroid is classified as an Apollo by JPL.
It is at perihelion at 0.59 au in 2017 September and has a period of 3.7 years. It does not approach
closely to Jupiter, but is an NEO and PHA with an Earth MOID of 0.011 au. It made a close approach on
July 22. It can also make close approaches to Venus and Mars. A team from the University of Ontario noted that the orbit was very close to that of the
Alpha Capricornid meteors and that the object might be a weakly active comet. [CBET 4415, 2017 August 2].
Peter Birtwhistle then re-examined his images of the object and noted a possible tail in images taken
on July 25. [CBET 4417, 2017 August 3]
A/2017 MZ4 [PanSTARRS]
PanSTARRS discovered a 19th magnitude asteroid in images taken with the 1.8m Ritchey-Chretien on
June 24.55. [MPEC 2017-M90, 2017 June 29]. The asteroid, classified by JPL as a Trans-Neptunian Object,
was at perihelion at 3.2 au in 2017 June and has a period of around 3000 years.
It was placed on the PCCP as P10BHYZ.
A/2017 MB7 [PanSTARRS]
PanSTARRS discovered a 22nd magnitude asteroid in images taken with the 1.8m Ritchey-Chretien on
June 22.31. [MPEC 2017-N23, 2017 July 1]. The asteroid, classified by JPL as a Trans-Neptunian Object,
was at perihelion at 4.5 au in 2016 December and has a period of around 3000 years.
It was placed on the PCCP as P10BDDW.
A/2017 MM7 [Mt Lemmon]
The Mt Lemmon Survey discovered a 20th magnitude asteroid in images taken with the 1.5m
reflector on June 26.35. [MPEC 2017-N20, 2017 July 1]
The asteroid is classified as an Apollo by JPL.
It was at perihelion at 0.084 au in 2017 May and the orbit has an eccentricity of 0.96.
There is no evidence for cometary activity, however the perihelion distance is comparable to that of some SOHO comets.
A/2017 NM2 [PanSTARRS]
PanSTARRS discovered a 22nd magnitude asteroid in images taken with the 1.8m Ritchey-Chretien on
July 6.46. [MPEC 2017-N67, 2017 July 11]. The asteroid, classified by JPL as a Centaur,
was at perihelion at 5.5 au in 2017 March and has a retrograde orbit with a period of around 56 years.
2017 O1 (ASASSN)
The All-Sky Automated Survey for Supernovae (ASASSN) discovered a 15th magnitude comet with the "Cassius" 14cm telescope at Cerro Tololo on
July 19.32. [CBET 4414, MPEC 2017-O45, 2017 July 24] After considerable discussion, the IAU "Working Group for Small Body
Nomenclature" (formerly the IAU "Committee for Small Body Nomenclature" and
the IAU "Small Bodies Names Committee") decided to accept the name
"ASASSN" for the comet [CBET 4426, 2017 August 26]. The comet reached perihelion at 1.5 au in 2017 October. Even before the discovery
announcement JJ Gonzalez had made a visual observation estimating the comet at 10th magnitude.
Several people have suggested that it must be in outburst, otherwise it should
have been detected earlier. The initial light curve suggested that it was
brightening moderately rapidly, however as observations accumulated it became clear that the brightness was not increasing with solar distance.
It is now conveniently placed in the evening sky and will still be well placed for observing at the end of the year, though is likely to slowly
fade from 9th magnitude.
2017 O2 (356P/WISE)
PanSTARRS discovered a 21st magnitude comet on July 30.54, which appeared on the PCCP as P10Cawe, but was soon linked to 2010 D1 (P/WISE).
[CBET 4416, MPEC 2017-P09, 2017 August 3]
2017 O3 (358P/PanSTARRS)
A comet, discovered by PanSTARRS on 2012 October 6, was recovered on 2017 July 1.37 with the Gemini South 8.1m reflector.
[MPEC 2017-Q115, 2017 August 25]

The orbital determinations have a rather complicated history, which are partialy elucidated under the entries for comets
282P and 358P

A/2017 OX68 [PanSTARRS]
PanSTARRS discovered a 22nd magnitude asteroid in images taken with the 1.8m Ritchey-Chretien on
July 26.30. [MPEC 2017-Q105, 2017 August 24]. The asteroid, classified by JPL as a Trans-Neptunian Object,
is at perihelion at 1.7 au in 2017 October and has a period of around 450 years, with an orbital inclination of 95 degrees.
Aphelion is at over 100 au. It has a Jupiter MOID of 0.0094 au. It was placed on the PCCP as P10BWk4.
2017 P1 (P/PanSTARRS)
A 21st magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on August 15.41.
There were also pre-discovery images from June 25, July 27 and August 12.
It had been posted on the PCCP as P10CrkQ.
[CBET 4420, MPEC 2017-Q12, 2017 August 17] The comet is at perihelion at 5.4 au in 2018
June and has a period of about 22 years. It is a Jupiter-family Comet and has a Jupiter MOID of 0.78 au.
2017 P2 (PanSTARRS)
A 22nd magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on August 14.26.
It had been posted on the PCCP as P10Cplr.
[CBET 4423, MPEC 2017-Q99, 2017 August 23] The comet is at perihelion at 2.5 au in 2017
December.
2017 Q1 (357P/Hill)
PanSTARRS recovered 2008 T4 with the 1.8m Ritchey-Chretien on August 18.49.
There were also pre-recovery images from July 25.
[CBET 4421, MPEC 2017-Q47, 2017 August 19]
2017 Q2 (359P/LONEOS)
PanSTARRS discovered a 21st magnitude comet with the 1.8m Ritchey-Chretien on 2017 August 22.48. Gareth Williams then identified it
with an apparently asteroidal object, 2007 RS41, found at Lowell Observatory in the course of
the LONEOS project in images taken by J. J. Sanborn with the 0.59-m LONEOS
Schmidt telescope on 2007 August 21.39.
[CBET 4424, MPEC 2017-Q116, 2017 August 25]
A/2017 QO33 [PanSTARRS]
PanSTARRS discovered a 21st magnitude asteroid in images taken with the 1.8m Ritchey-Chretien on
August 16.49. [MPEC 2017-Q161, 2017 August 31]. The asteroid, classified by JPL as a Trans-Neptunian Object,
is at perihelion at 4.9 au in 2018 May and has a retrograde orbit with a period of around 200 years.
2017 R1 (P/PanSTARRS)
A 21st magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on September 14.41.
There were also pre-discovery images from July 30, August 1, 3, 17 and Mt Lemmon from September 2.
It had been posted on the PCCP as P10D5ss.
[CBET 4430, MPEC 2017-S97, 2017 September 22] The comet was at perihelion at 3.3 au in 2017
April and has a period of about 8 years. JPL classify it as an Encke-type Comet and it has a Jupiter MOID of 0.41 au.
A/2017 RS [PanSTARRS]
PanSTARRS discovered a 20th magnitude asteroid in images taken with the 1.8m Ritchey-Chretien on
September 1.35. [MPEC 2017-R36, 2017 September 7]. The asteroid, classified by JPL as an Outer Main-belt asteroid,
is at perihelion at 1.6 au in 2017 November and has an orbit with a period of around 8 years. It has a Jupiter MOID of 0.35 au.
A/2017 RR2 [PanSTARRS]
PanSTARRS discovered a 22nd magnitude asteroid in images taken with the 1.8m Ritchey-Chretien on
September 14.32. [MPEC 2017-S21, 2017 September 17]. The asteroid, classified by JPL as a Centaur,
is at perihelion at 2.6 au in 2018 January and has an orbit with a period of around 70 years. Some of the orbital elements are very
uncertain.
A/2017 RW15 [PanSTARRS]
PanSTARRS discovered a 20th magnitude asteroid in images taken with the 1.8m Ritchey-Chretien on
September 15.40. [MPEC 2017-S50, 2017 September 18]. The asteroid, classified by JPL as an Outer Main-belt asteroid,
was at perihelion at 2.0 au in 2017 July and has an orbit with a period of around 9 years. It has a Jupiter MOID of 0.09 au,
though there have been no recent close passes. Some of the orbital elements are very uncertain.
A/2017 RF16 [PanSTARRS]
PanSTARRS discovered a 20th magnitude asteroid in images taken with the 1.8m Ritchey-Chretien on
September 12.39. [MPEC 2017-S59, 2017 September 20]. The asteroid, classified by JPL as a Centaur,
was at perihelion at 2.5 au in 2017 August and has an orbit with a period of around 18 years. It has a Jupiter MOID of 0.40 au,
though there have been no recent close passes.
2017 S1 (360P/WISE)
The ESA Optical Ground Station at Tenerife recovered 2010 P4 with the 1.0m telescope on September 20.10.
[CBET 4429, MPEC 2017-S90, 2017 September 20]
2017 S2 (PanSTARRS)
A 21st magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on September 16.50.
It had been posted on the PCCP as P10DfyE.
[CBET 4431, MPEC 2017-S98, 2017 September 22] The comet was at perihelion at 3.6 au in 2017
August. It has a period of around 100 years and JPL classify it as a Jupiter-family comet, as it is in a prograde orbit.
2017 S3 (PanSTARRS)
A 21st magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on September 23.24.
It had been posted on the PCCP as P10DwLA.
[CBET 4432, MPEC 2017-S160, 2017 September 27] The comet was at perihelion at 0.2 au in 2018
August. It was reported as unexpectly bright in images taken by Michael Jager
on July 1, when compared to the previous day, with an estimated magnitude of 9.
It was not clear at the time whether this was an outburst or the coma passing a
threshold. The comet passed into conjunction and was not recovered when it
emerged. JJ Gonzalez was however able to see the faint cloud of material that
was all that remained of the comet in October and November. Zdenek
Sekanina and Rainer Kracht have written a paper on the comet's demise.
2017 S4 (361P/Spacewatch)
A comet discovered by PanSTARRS on 2017 September 24.29 was linked to an
asteroid discovered by Spacewatch on 2006 October 19.13. It was designated as 2006 UR111 at that return.
[CBET 4433, MPEC 2017-S197, 2017 September 28] The comet is at perihelion at 2.8 au in 2018
July and has a period of 11 years. It may have undergone a minor outburst, as it was 21st magnitude on September 11, and
19th magnitude on September 27.
2017 S5 (P/ATLAS)
An 18th magnitude comet was discovered in images taken with the 0.5m Schmidt at Haleakala on September xx
by the ATLAS (Asteroid Terrestrial-impact Last Alert System) team. It had been posted on the PCCP as A104e5G.
[CBET 4434, MPEC 2017-S213, 2017 September 29]. The comet was at perihelion at 2.2 au in 2017 July and has a period of around 6 years.
2017 S6 (Catalina)
A 20th magnitude comet was discovered by the Catalina Sky Survey with the 0.68m Schmidt on September 30.41.
[CBET 4437, MPEC 2017-T37, 2017 October 8] It had been posted on the NEOP as YS21DA8.
The comet is at perihelion in 2018 February at 1.5 au.
2017 S7 (Lemmon)
A 20th magnitude object was discovered in Mt Lemmon Survey images taken with the
1.5m reflector on September 26.46. It had been posted on the PCCP as YSB07CS. Pre discovery images from
2016 December from Mt Lemmon were found.
[CBET 4438, MPEC 2017-T38, 2017 October 8] The comet was at perihelion at
7.6 au in 2017 May.
2017 S8 (P/PanSTARRS)
A 20th magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on September 30.54.
There were pre-discovery Catalina images from September 25 and 29.
It had been posted on the PCCP as P10E1ZQ.
[CBET 4446, MPEC 2017-U236, 2017 October 28] The comet is at perihelion at 1.7 au in 2018
January. It has a period of 4.6 years and JPL classify it as a Encke-family comet.
2017 S9 (P/PanSTARRS)
A 22nd magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on September 30.59.
There were pre-discovery PanSTARRS images from September 19.
It had been posted on the PCCP as P10E2ep.
[CBET 4448, MPEC 2017-U237, 2017 October 28] The comet was at perihelion at 2.2 au in 2017
July. It has a period of 5.6 years and JPL classify it as a Encke-family comet.
A/2017 SW11 [PanSTARRS]
PanSTARRS discovered a 21st magnitude asteroid in images taken with the 1.8m Ritchey-Chretien on
September 21.51. [MPEC 2017-S131, 2017 September 25]. The asteroid, classified by JPL as a Centaur,
is at perihelion at 4.7 au in 2019 October and has an orbit with a period of around 30 years. It has a Jupiter MOID of 0.39 au,
though there have been no recent close passes.
A/2017 SV13 [PanSTARRS]
PanSTARRS discovered a 21st magnitude asteroid in images taken with the 1.8m Ritchey-Chretien on
September 17.49. [MPEC 2017-S156, 2017 September 27]. The asteroid, classified by JPL as a Centaur,
was at perihelion at 2.0 au in 2017 August and has a retrograde orbit with a period of around 35 years.
A/2017 SL21 [PanSTARRS]
PanSTARRS discovered a 19th magnitude asteroid in images taken with the 1.8m Ritchey-Chretien on
September 26.55. [MPEC 2017-T21, 2017 October 7]. The asteroid, classified by JPL as a Centaur,
was at perihelion at 2.3 au in 2017 May and has a period of around 19 years. It has a Jupiter MOID of 0.24 au.
A/2017 SN33 [PanSTARRS]
PanSTARRS discovered a 20th magnitude asteroid in images taken with the 1.8m Ritchey-Chretien on
September 19.55. [MPEC 2017-U156, 2017 October 22] The asteroid, classified as a Trans-Neptunian Object,
was at perihelion at 1.8 au in 2017 September and has a retrograde orbit with a period of around 5000 years. It was placed on the PCCP
as P10Dm7L. No cometary activity has been detected.
2017 T1 (Heinze)
Aren (Ari) Heinze discovered an 18th magnitude comet in images taken with the ATLAS (Asteroid Terrestrial-impact Last Alert System) 0.5m Schmidt
at Mauna Loa, Hawaii on September 28.60. It had been posted on the PCCP as A104nX1.
[CBET 4444, MPEC 2017-U15, 2017 October 16]. The comet will reach perihelion at 0.6 au in 2018 February and passes around 0.2 au from Earth
in 2018 January. The orbit has an Earth MOID of 0.014 au, so an associated meteor shower may be a possibility. The comet could be a
telescopic object from December to early February, but becomes poorly placed around the time of perihelion. It is well placed during
closest approach to Earth, when it may be 10th magnitude.
2017 T2 (PanSTARRS)
A 20th magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on October 2.52. There were
pre-discovery PanSTARRS images from September 15.
It had been posted on the PCCP as P10E7lu.
[CBET 4445, MPEC 2017-U180, 2017 October 25] The comet is at perihelion at 1.6 au in 2020
May. It could become a nice object during 2020 if the present rate of
brightening continues.
JJ Gonzalez picked it up visually in 2019 March, roughly in line with the magnitude
expected if the electronic observations are corrected for aperture. The
likely peak brightness is still extremely uncertain, ranging from faint
binocular to naked eye visibility.
2017 T3 (ATLAS)
An 18th magnitude comet was discovered in images taken with the 0.5m Schmidt at Haleakala on October 14.35
by the ATLAS (Asteroid Terrestrial-impact Last Alert System) team. There were pre-discovery PanSTARRS images
from September 11. It had been posted on the PCCP as A104VfJ.
[CBET 4449, MPEC 2017-U238, 2017 October 28]. The comet will reach perihelion at 0.8 au in 2018 July. Sadly,
although the comet's orbit comes close to that of the Earth the comet does not. It is poorly placed around
the time of perihelion, though Southern Hemisphere observers may get a glimpse of it. It
was observed at 9th
magnitude in 2018 July.
A/2017 TC1 [Mt Lemmon]
The Mt Lemmon Survey discovered a 21st magnitude asteroid in images taken with the 1.5m
reflector on October 1.37. [MPEC 2017-T28, 2017 October 7]
The asteroid is classified as an Apollo by JPL, though it has some similarity to an extinct comet.
It is at perihelion at 0.076 au in 2017 November and has a highly eccentric orbit with a period of around 3.9 years.
It has a Jupiter MOID of 0.87 au and a Tisserand invariant of 2.43. It is intrinsically faint, but passes through
the SOHO field in late November. If it is just an asteroid it would not get brighter than 16th magnitude and so remain
invisible.
2017 TW13 (P/Lemmon)
The Mt Lemmon Survey discovered a 20th magnitude asteroid in images taken with the 1.5m
reflector on October 13.17. [MPEC 2017-U243, 2017 October 28]
The asteroid was originally classified as a Centaur by JPL.
It was at perihelion at 2.1 au in 2018 June and has an eccentric orbit with a period of 19.2 years.
It has a Jupiter MOID of 0.35 au and a Tisserand invariant of 1.90. It might be worth monitoring to see if
develops any cometary activity. It had been posted on the PCCP as YTBE6EF.

As suggested in 2017, it was worth monitoring for cometary activity, and it showed such features when
recovered in 2018 October.

2017 U1 (1I/'Oumuamua)
A 20th magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on October 18.47.
It had been posted on the PCCP as P10Ee5V.
[CBET 4450, MPEC 2017-U181, 2017 October 25] The comet was at perihelion at 0.3 au in 2017
September. The orbit has an Earth MOID of 0.09 au and passed 0.16 au from
the Earth on October 14. The comet has very faint absolute magnitude. Gareth Williams noted on MPEC 2017-U181:

Further observations of this object are very much desired. Unless there
are serious problems with much of the astrometry listed below, strongly
hyperbolic orbits are the only viable solutions. Although it is probably
not too sensible to compute meaningful original and future barycentric orbits,
given the very short arc of observations, the orbit below has e ~ 1.2 for
both values. If further observations confirm the unusual nature of this
orbit, this object may be the first clear case of an interstellar comet.

Gareth Williams further noted on MPEC 2017-U183 later the same day:

K. Meech (Institute of Astronomy, University of Hawaii) reports that in a
very deep stacked image, obtained with the VLT, this object appears completely
stellar. The prefix for the designation 2017 U1 is therefore being changed to
A/, in line with the 1995 IAU Resolution on the system of comet designations.

With further observations the interstellar nature of the object was confirmed and a new designation system
was therefore required. This was described in MPEC 2017-V17
[2017 November 6] in which the object was formally named 1I/'Oumuamua.
The ' is part of the name.

A paper published in Nature on 2018 June
28 by Marco Micheli et al reports that the object shows a non-gravitational
acceleration and suggests that it is in fact a comet. It would have a
rather unusual composition to explain the spectral observations and have to emit
little dust, though what dust it does emit might be similar to 2P/Encke.
They discuss other possible explanations for a non-gravitational acceleration,
but not that shown by spacecraft.
2017 U2 (Fuls)
D Carson Fuls discovered a 21st magnitude comet in Mt Lemmon Survey images taken with the
1.5m reflector on October 22.08. Following this, pre-discovery images were found in PanSTARRS data from
September 8.
[CBET 4451, MPEC 2017-U239, 2017 October 28] The comet was at perihelion at 6.7 au in 2017
August.
2017 U3 (P/PanSTARRS)
A 20th magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on October 19.50.
There were pre-discovery PanSTARRS images from October 1.
It had been posted on the PCCP as P10Es3z.
[CBET 4452, MPEC 2017-V48, 2017 November 13] The comet is at perihelion at 4.4 au in 2019
April. It has a period of 11 years and JPL classify it as a Jupiter-family comet.
2017 U4 (PanSTARRS)
A 22nd magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on October 27.58.
It was posted on the PCCP as P10EpAX.
[CBET 4454, MPEC 2017-W52, 2017 November 19] The comet is at perihelion at 7.7 au in 2018
September.
2017 U5 (PanSTARRS)
A 21st magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on October 30.51.
It was posted on the PCCP as P10EAI6.
[CBET 4456, MPEC 2017-X6, 2017 December 2; Note: the comet was mistakenly designated U4 on the
original CBET and CBET 4458 was issued on December 3 with the correct
designation] The comet is at perihelion at 4.3 au in 2017
December and has a period of around 70 years.
2017 U6 (365P/PanSTARRS)
An apparently asteroidal object of 21st magnitude was discovered in PanSTARRS images
taken with the 1.8m Ritchey-Chretien
on 2011 November 24.29 and also observed on 2011 December 2. This was designated 2011 WG113.
The object was re-discovered by PanSTARRS on 2017 October 21.43, still appearing as asteroidal.
Subsequent observations in 2018 February by the Catalina and Mt Lemmon telescopes showed a
diffuse coma and tail, so it was designated as 2017 U6.
[CBET 4490, MPEC 2017-D88, 2018 February 27] The CBET is likely to be replaced by a follow-up,
as there are grammatical errors. The comet was at perihelion at 1.4 au in 2018
February. It has a period of 5.7 years and JPL classify it as a Jupiter-family comet.
2017 U7 (A/PanSTARRS)
An asteroidal object of 20th magnitude was discovered in PanSTARRS images
taken with the 1.8m Ritchey-Chretien on 2017 October 29.33. The orbit is slightly hyperbolic, but
despite much imaging no coma has been detected. It was therefore given a cometary letter
designation with an A/ prefix.
[CBET 44xx, MPEC 2017-E17, 2018 March 4] The asteroid is at perihelion at 6.4 au in 2019
September.
A/2017 UR7 [Mt Lemmon]
The Mt Lemmon Survey discovered a 20th magnitude asteroid in images taken with the 1.5m
reflector on October 26.23. [MPEC 2017-U255, 2017 October 29]
The asteroid is classified as an Amor by JPL.
It is at perihelion at 1.12 au in 2018 January and has a period of around 5.8 years.
It has a Jupiter MOID of 0.05 au and a Tisserand invariant of 2.80.
A/2017 UW51 [Mt Lemmon]
The Mt Lemmon Survey discovered a 20th magnitude asteroid in images taken with the 1.5m
reflector on October 23.37. [MPEC 2017-V46, 2017 November 12]
The asteroid is classified as Trans-Neptunian Object by JPL.
It is at perihelion at 3.13 au in 2018 February and the retrograde orbit has a period of around 1600 years.
Aphelion is at around 270 au. It had been posted on the PCCP as YU9F4AA. No cometary activity has been detected.
A/2017 UX51 [PanSTARRS]
PanSTARRS discovered a 22nd magnitude asteroid in images taken with the 1.8m Ritchey-Chretien on
October 27.52. [MPEC 2017-V47, 2017 November 12] The asteroid, classified as a Trans-Neptunian Object,
was at perihelion at 7.6 au in 2022 August and has a near perpendicular orbit with a period of around 180 years. It was placed on the PCCP
as P10EpAY. No cometary activity has been detected.
A/2017 UR52 [Mt Lemmon]
The Mt Lemmon Survey discovered a 20th magnitude asteroid in images taken with the 1.5m
reflector on October 29.33. [MPEC 2018-C45, 2018 February 9]
The object is classified as an Amor asteroid by JPL and is an NEO as it has an Earth MOID of 0.32 au. It approached to
this distance on November 1, shortly after discovery.
It was at perihelion at 1.24 au in 2017 October and the slightly retrograde orbit has a nominal period of around 8000 years.
Aphelion is at around 800 au. It had been posted on the PCCP as YUB0764 for several months, but no cometary
activity was detected and it is now probably too distant to show any.
A/2017 VT14 [NEOWISE]
A 21st magnitude asteroid was discovered from the NEOWISE satellite on November 13.77. [MPEC 2017-W30, 2017 November 17]
The asteroid, classified as an Apollo, is at perihelion at 1.0 au in 2017
December and has a period of around 6.3 years. The
orbit has a Jupiter MOID of 0.15 au and a Tisserand invariant of 2.65. It passed 0.010 au from the Earth on December 17.
2017 W1 (363P/Lemmon)
Paplo Ruiz recovered 2011 VJ5 (P/Lemmon) on November 19.13 using a 1.0-m f/4.4
reflector at the European Space Agency's Optical Ground Station, Tenerife,
Spain. It was confirmed the following night, and then additional images from October and earlier in
November were found by Gareth Williams. The indicated correction to the prediction by S. Nakano is Delta(T) = +1.04 day.
[CBET 4455, MPEC 2017-W73, 2017 November 19/20].
2017 W2 (Leonard)
Greg Leonard discovered a 20th magnitude comet in Mt Lemmon Survey images taken with the
1.5m reflector on November 26.46. It was placed on the PCCP
as YW9CAED.
[CBET 4461, MPEC 2017-Y43, 2017 December 19] The comet was at perihelion at 4.0 au in 2017
November
and has a period of around 50 years.
2017 W3 (P/Gibbs)
Alex Gibbs discovered a 19th magnitude comet during the Catalina Sky Survey with the 0.68m Schmidt on November 27.52.
[CBET 4462, MPEC 2017-Y44, 2017 December 19] It had been posted on the NEOP as YWIE5D2.
The comet is at perihelion in 2018 February at 3.8 au and has a period of around 21 years.
A/2017 WH29 [PanSTARRS]
PanSTARRS discovered a 21st magnitude asteroid in images taken with the 1.8m Ritchey-Chretien on
November 17.25. The asteroid, classified as a Main-belt Asteroid,
was at perihelion at 2.1 au in 2017 May and has a period of 4.2 years. It was placed on the PCCP
as P10EQeq. No cometary activity has been detected.
2017 X1 (PanSTARRS)
A 20th magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on December 12.56.
It was posted on the PCCP as P10FsNw.
[CBET 4463, MPEC 2017-Y45, 2017 December 19] The comet is at perihelion at 4.7 au in 2018
June and has a period of around 170 years.
2017 Y1 (PanSTARRS)
A 21st magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on December 24.57.
It had been posted on the PCCP as P10FFVk.
[CBET 4465 and 4466 (designation corrected), MPEC 2017-Y159, 2017 December 30] The comet was at perihelion at 3.7 au in 2017
August.
2017 Y2 (PanSTARRS)
A 22nd magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on December 24.21.
It had been posted on the PCCP as P10FGdo.
[CBET 4467, MPEC 2017-Y160, 2017 December 30] The comet is at perihelion at 4.0 au in 2020
September.
2017 Y3 (P/Leonard)
Greg Leonard discovered a 19th magnitude comet in Mt Lemmon Survey images taken with the
1.5m reflector on December 26.53. It was placed on the PCCP
as YY89879.
[CBET 4469 and 4470 (which corrected a spelling mistake in 4469), MPEC 2018-A42, 2018 January 11] The comet is at perihelion at 1.3 au in 2018 February
and has a period of around 30 years.
A/2017 YE5 [Rinner]
Claudine Rinner discovered a 2oth magnitude asteroid in images taken with the 0.5m reflector at the Oukaimeden Observatory,
Marrakech on December 21.01. The asteroid, classified as an Apollo,
is at perihelion at 0.82 au in 2018 May and has a period of 4.7 years. The orbit has a Earth MOID of 0.021 au and
and a Jupiter MOID of 0.43 au, with a Tisserand invariant of 2.88. It will pass 0.04 au from the Earth on June 21,
and 0.05 au from Mars on July 30. Radar imaging during this approach
showed that it was an equal mass binary with each component about 900m in
diameter and orbiting each other in 20-24 hours. The components are
optically dark and it could be an extinct comet.
Ephemerides of current comets are available on the CBAT
ephemeris page and positions of newly discovered comets are on the
Possible Comet Confirmation Page.
More information on LINEAR. A list of comets
discovered by selected search programs.
Published by Jonathan Shanklin. Jon Shanklin - jds@ast.cam.ac.uk